A pyrrolopyrimidine ring is known as a partial structure commonly possessed by many kinase inhibitors (Non-patent Literature (NPL) 3 and Non-patent Literature (NPL) 4).
The method disclosed in Patent Literature (PTL) 1 has been known as a method for producing a pyrrolopyrimidine ring-containing tricyclic compound.
In the method disclosed in PTL 1, an organic borane reagent is caused to act on a pyrrolopyrimidine derivative to prepare an alkyl borane intermediate in the system, and an intramolecular cyclization reaction is then performed using a divalent palladium catalyst to thereby produce a pyrrolopyrimidine ring-containing tricyclic compound. However, this method suffers from low yield, as shown in Comparative Example 1 below.
The intramolecular cyclization reaction using a zerovalent palladium catalyst has also been known (Non-patent Literature (NPL) 1 and Non-patent Literature (NPL) 2).
NPL 1 reports a method that uses a zerovalent palladium catalyst and cesium carbonate as a base. However, this method also suffers from low yield, as shown in Comparative Example 2 below.
NPL 2 reports a method that uses a zerovalent palladium catalyst and thallium carbonate as a base. However, thallium carbonate is an acute toxic substance and is not preferably used in a production method.